P2: fix will likely be wanted for continued usage

Keeping binaries in the repository would mean a noticeable increase in repo size
after every update to a new version of a third-party library.
Currently working around; details: ExternalBinaries.
But it would be much preferable to be able to logically keep binaries in the repository
yet avoid pulling them until they are really needed:
TrimmingHistory

There is no simple way to see what a merge changeset changed
beyond what a "simple" automated merge would have done.
Hg RFE #981

No extension in standard distro with "shelve" functionality.
hgattic seems to work well,
but few developers are going to download and enable a third-party extension.

hg revert -r ... on an uncommitted merge should issue a very strict warning.
(The warning should explain to use hg up -C to start over.)
Run by an inexperienced user, it can result in other changesets being "silently" backed out.
as yet unfiled, but see Hg bug #2915

merging c8cc42c09f2d with ad26ef8112a1 (as in 8c3708e43df4) results in anomalous conflict in cnd.gizmo/src/org/netbeans/modules/cnd/gizmo/RemoteJarServiceProvider.java;
similarly, merging 5e75c5aaf5bb with d6166c5823c9 (as in 9995bbea1af5) results in anomalous conflict in maven/manifest.mf.
Problem also between 171b2ae20e87 and e571741a7430 using Hg 2.1.
Same with 69e783c53a7e and 3c888c7e6c1f (-> 10b5913e74e3).
Same with 175addc1cc09 and c47ec08fc66d.
(as yet unfiled)

strace hg di -r release65_base o.n.bootstrap/src/org/netbeans/TopSecurityManager.java
shows every file in the checkout being stat'd, for no apparent reason.
as yet unfiled

hg bisect does not work well with merges.
E.g. run

hg bisect -b de345c4fe13f
hg bisect -g be85c2e1048d

and then mark any revision good if it contains
nbbuild/test/unit/src/org/netbeans/nbbuild/data/Category.png
and you wind up with c429f829c9f3 being blamed,
though this is not a descendant of the good revision.
as yet unfiled

Possible merge bug (symptoms fixed in 69dcf3fcc35d). phejl says "I removed tomcat.obsolete on branch (module and line in cluster.properties); sg-nb reverted some of his changes, mistakenly removing tomcat.obsolete line from cluster.properties on trunk (bdfefc80db7c); sg-nb added tomcat.obsolete to cluster.properties on trunk (c45b7baf4478); I merged the branch to trunk; tomcat.obsolete module removed on trunk, but still in cluster.properties". Sounds like the merge (996de2fd4b52?) somehow did not work correctly - should have either resulted in the entry being missing from cluster.properties, or a merge conflict. Maybe http://mercurial.selenic.com/bts/issue1740 or maybe something else. But ca913542dad4 (last serverplugins-next) still has tomcat.obsolete listed. (phejl says he definitely didn't readd it on the branch manually; maybe it was merged from trunk as he made couple of trunk -> branch merges.)
(as yet unfiled)

Irrelevant changes to file mode, e.g. in 08f1e909c26c, cannot be suppressed; about 20% of files in the main repo are g+w, for no apparent reason, and changes to such modes (perhaps only on Windows?) appear in the file log.
(as yet unfiled)

If you update a dirty checkout and .hgignore changes as a result, it is possible for previously ignored files (e.g. build products from a renamed module) to become no longer ignored, yet there is no warning that this has happened or that it might be safe to delete these files.
as yet unfiled

While you can translate LF <-> CRLF on the client,
there is no standard server hook to prevent line ending accidents.
Hg RFE #882
(The associated patch can be used without being accepted into Hg proper.)
Fixed in Hg 1.0 and installed as push hook on server.

Merging in the presence of named branches can be confusing.
Hg bug #756We will not use named branches for now.

Some operations are unnecessarily slow on Windows.
Hg bug #952(fixed in 1.0)

Specific error messages from server pre-push hooks are not displayed to an HTTPS client.
Hg bug #937(fixed in 1.0, patch applied to live server)

The order of merge parents for hg fetch is often misleading.
Hg RFE #1011(fixed in 1.0)

Merge restores deleted files if you had locally deleted them but did not commit the delete.
Hg bug #988(fixed in 1.0, working around with server hook to prevent damage from being propagated)

Hg does not prevent you from committing only some files from a merge.
Hg bug #1049(fixed in 1.0)

INotify extension is not bundled in the standard distro.
Hg RFE #809(in 1.0, still discouraged for use)

Diffing some files can be slower in Hg 1.0 than in 0.9.5.
Hg bug #1090(fixed in dev)

Renaming SubSet.java to Subset.java might cause an error for a Windows user trying to update sources.
Hg bug #750(fixed in dev)
There are other potential problems with case collisions on Windows.
Hg bug #593(fixed in 1.1)

Some operations, especially hg clone -r, fail to use hardlinks aggressively enough;
this can result in unnecessarily large repository storage when using multiple repositories.
Hg RFE #919(new relink extension in dev)